A team of mathematicians has devised the most precise recipe yet for blowing perfect bubbles, and it’s not just for fun and frolics. Achieving a better understanding of the dynamics at work could lead to more efficient industrial production of commercial sprays and foams, like shaving cream or Reddi-Wip—pretty much anything that has drops or bubbles in it.
Bubbles have long been serious science. Back in the 1800s, Belgian physicist Joseph Plateau outlined four basic laws of surface tension that determine the structure of soapy films. Surface tension is why bubbles are round; that shape has the least surface area for a given volume, so it requires the least energy to maintain. (As gravity pulls the liquid downward in a process known as coarsening, the shape starts to look more like a soccer ball rather than a perfect sphere.) American botanist Edwin Matzke used to build foams by hand in his lab in the 1940s, bubble by bubble, the better to examine their structure.
More recently, Irish mathematicians used computer modeling in 1994 to determine the best geometric shape bubbles can take for most efficient packing, while other scientists have used acoustic levitation—powerful sound waves—to suspend bubbles in mid-air. In 2006, Harvard University scientists figured out that adding tiny colloidal particles to the mix created a kind of coating or armor, producing much more stable bubbles that could be reshaped and molded at will. It’s even possible to build rudimentary microfluidic bubble-based logic devices to transport therapeutic drugs or chemical reagents.